Senior Machine Learning Engineer II

About SumUp

SumUp's mission is to level the playing field for small businesses by providing simple and affordable tools for payments, finance, and customer relationships. We are a passionate, global team of 3,000+ people from over 90 nationalities, united by our values: Founder's Mentality, Team First, and We Care. We strive to build an enduring, people-positive, and innovative organization.

The Opportunity: Senior AI/ML Engineer

In Global Operations, we are dedicated to creating the best customer experience in fintech. This role is essential for developing and deploying the next generation of AI-driven solutions that automate support and dramatically enhance the experience for both our merchants and support agents. You will be a key expert responsible for building and maintaining the ML infrastructure and tooling that powers our core products using advanced AI/ML models. This is a replacement role, crucial for maintaining momentum as we expand complex use cases like our AI Assistant and translation tools.

What You'll Be Doing

• Serve as the dedicated technical leader for the Operations AI team, focusing on designing, developing, and deploying high-performance, scalable ML/AI solutions in production.
• Architect, design, develop, and deploy AI solutions and systems into production, ensuring reliability, high performance, and scalability.
• Lead the technical development and maintenance of core AI products, including the AI Assistant (automating ~40% of merchant requests), AI Translation (enabling cross-language agent service), and the AI Agent Copilot.
• Develop and maintain ML infrastructure and pipelines for efficient data processing, model training, serving, and continuous monitoring.
• Optimize and fine-tune machine learning models, and process large text datasets for high-quality model training and evaluation.
• Apply software development principles, best practices, and industry standards (Git, CI/CD, unit testing).
• Collaborate closely with Data Scientists, Product Managers, Developers, and other stakeholders to improve customer experience and operational efficiency.
• Rapidly master the existing AI assistant infrastructure, focusing on behavior improvements and agentic rollouts.
• Lead the pilot for the Voice Assistant and strategize on leveraging current AI assistant components for new channels.

You'll Be Great for This Position If You Have

• 7+ years of proven experience as a Machine Learning Engineer or AI Engineer, specializing in building and deploying scalable ML/AI solutions and data-driven systems.
• Expert-level Python proficiency and strong software development engineering skills for large-scale production environments.
• Substantial prior experience as an ML or AI engineer with models in production, coupled with a deep understanding of AI, ML, and deep learning concepts.
• Experience using GenAI/LLM APIs and evaluating LLM models in production.
• Experience building and deploying ML Models using cloud platforms (AWS, GCP, or Azure).
• Familiarity with MLOps tools (e.g., MLFlow, Kubeflow, Airflow, Langfuse) and hands-on experience with Kubernetes, Git, and Airflow.
• Good understanding of data pipelines, API design, containers (Docker), and version control (Git).
• Experience building, maintaining, and scaling APIs, and deploying using CI/CD Pipelines in GitHub actions.
• A strong team player attitude, thriving on cross-functional collaboration.
• Self-driven, proactive, and highly adaptable in a fast-paced environment, with a commitment to data governance, quality, and ownership.
• A passion for AI Technology, eagerness to power SumUp's automated support tools, and the ability to translate complex concepts to non-technical stakeholders.

Why You Should Join SumUp

• Global Impact: Work with SumUppers globally on large-scale fintech products used by millions of businesses, based in our Berlin office (office-first setup).
• Diversity & Inclusion: Be part of a workplace that values and promotes diversity, fostering an inclusive environment.
• Virtual Stock Option Programme: Own a stake in SumUp's future success.
• Learning & Development: Receive a dedicated annual L&D budget of €2000 for conferences and further education.
• Pension Scheme: Benefit from a corporate pension scheme with up to 20% employer match.
• Generous Time Off: Enjoy 28 days of paid leave plus public holidays and special leave days.
• Additional Benefits: Access to Urban Sports Club subsidy, Kita placement assistance, and subsidized office lunches.
• Break4me: A 1-month sabbatical after 3 years of service.
• Referral Bonus: Earn rewards by referring talented individuals.

About SumUp (Further Details)

SumUp is committed to empowering small businesses worldwide with simple, affordable tools. Over 4 million merchants trust us as their financial partner. We are a global team of 3,000+ people from over 90 nationalities, united by curiosity, collaboration, and care. Our core values and culture foster inclusion, learning, and belonging. SumUp is proud to be an Equal Employment Opportunity employer, committed to building a safe, respectful, and diverse workplace.

Job Application Tip: While meeting 100% of criteria is a guide, we encourage you to apply even if you don't tick every box, as there's room for learning and development at SumUp.